Field of the Invention
The present invention relates to a metal nitride film for a thermistor, which can be directly deposited on a film or the like without firing, a method for producing the same, and a film type thermistor sensor.
Description of the Related Art
There is a demand for a thermistor material used for a temperature sensor or the like having a high B constant in order to obtain a high precision and high sensitivity temperature sensor. Conventionally, transition metal oxides such as Mn, Co, Fe, and the like are typically used as such thermistor materials (see Patent Documents 1 and 2). These thermistor materials also need firing at a temperature of 600° C. or higher in order to obtain a stable thermistor characteristic/property.
In addition to thermistor materials consisting of metal oxides as described above, Patent Document 3 discloses a thermistor material consisting of a nitride represented by the general formula: MxAyNz (where “M” represents at least one of Ta, Nb, Cr, Ti, and Zr, “A” represents at least one of Al, Si, and B, 0.1≤x≤0.8, 0<y≤0.6, 0.1≤z≤0.8, and x+y+z=1). In Patent Document 3, only a Ta—Al—N-based material consisting of a nitride represented by the general formula: MxAyNz (where 0.5≤x≤0.8, 0.1≤y≤0.5, 0.2≤z≤0.7, and x+y+z=1) is described as an Example. The Ta—Al—N-based material is produced by sputtering in a nitrogen gas-containing atmosphere using a material containing the element(s) listed above as a target. The resultant thin film is subject to a heat treatment at a temperature from 350 to 600° C. as required.